Hi, I Am 35 Year Old Married Women With Very

Hi, I am 35 year old married women with very regular periods. My LMP was 24th of Nov, 2016. I did not get my periods after that and ruled out pregnancy. My doctor advised me deviry 10 mg for 7 days twice a day. I have completed the regime on 2nd of February. I am yet to get my periods and noticed very meek brown spotting. Why is this happening and when should I expect to bleed?